Sliding sleeves in tubular strings have been moved in the past with direct application of hydraulic pressure applied to a sealed chamber where the sleeve acts as a piston. Rising pressure puts a force on the sleeve to change its position. This is a sleeve actuation method frequently used in subsurface safety valves such as in U.S. Pat. No. 4,473,122. Other ways of moving a sleeve are to use ball screws or similar mechanical devices to force a sleeve to translate or to rotate as shown in WO97/30269.
Sleeve valves are frequently used in fracturing where ports are covered by a sleeve when running in and subsequently opened for treatment. After treatment the ports are closed with sleeve movement and then need to be reopened when the entire zone is treated for production from the formation. One way this is done now is to shift a sleeve with pressure on a ball landed on a seat supported by the sliding sleeve so that the ports are opened for treatment. After the treatment through an opened valve is concluded another ball that is larger lands on the next sleeve uphole and in effect isolates the ports opened by the previous sleeve so that treatment at the next set of ports in an uphole direction can take place. This process is repeated with progressively larger balls until the entire interval is treated. After that, all the balls are drilled out and if needed certain sleeves are closed with a shifting tool before production begins through the open sleeves. There are drawbacks to this well-known method of fracturing or otherwise treating a formation. There can be a large number of balls that have to be delivered in size order that are only minimally different in diameter. This can cause operator confusion. The sleeves have seats that restrict the produced fluid flow to some degree. The milling is time consuming and creates debris in the borehole that can adversely affect the operation of other tools with small clearances.
Sliding sleeves can be individually moved with one or more control lines to each sleeve but using this technique in situations with many sleeves is expensive and time consuming. Another way is to send power to operators for sleeves through a wired system. This technique is also expensive and time consuming. Valve members have been designed to be pressure responsive to pressure cycling using unequal piston areas and a j-slot mechanism to operate a single sleeve. However, this design is not useful with arrays of valve members that need to be distinctly addressable to move in a predetermined sequence.
The method and apparatus of the present invention provides an interventionless way to open, then close and then reopen specific sliding sleeves so that a particular sleeve can provide access for treatment and then get closed as another sleeve is actuated to continue the treatment. Thereafter a selected sleeve can be reopened and optionally locked open for production. Ball seats and milling are eliminated allowing for production to begin that much faster. The movement of the sleeve is accomplished with signal responsive valves that direct tubing hydrostatic pressure to different piston areas on opposed sides of a piston to make the piston move in the direction desired. Tubing or annulus pressure can be employed if the annulus is not cemented. An option is available for intervention in the tubing such as with a straddle tool that can preferably equalize the piston areas on opposed sides of the piston and allow piston movement with pressure applied through the straddle packer tool. These and other aspects of the present invention will be more readily apparent from a review of the description of the preferred embodiment and the associated drawings while recognizing that the full scope of the invention is to be determined by the appended claims.